Power transmission apparatus in a motorized two-wheel vehicle

ABSTRACT

A motorized two-wheel vehicle has an engine supported from the frame via resilient damping members and the vehicle is provided with a power transmission from the engine to a rear wheel driven member such that the drive of the rear wheel is substantially unaffected by engine vibration. The power transmission comprises a drive member driven from the output shaft of the engine by a universal joint, the drive member being coupled to the driven member by a transmission member such as a chain, the driven member being connected at the free end of a fork having its other end pivotably connected to the frame.

United States Patent [191 Watanabe et al.

[ 1 POWER TRANSMISSION APPARATUS IN A MOTORIZED TWO-WHEEL vmnctr:

[73] Assignee: Honda Giken Kogyo Kabushikl Keisha, Tokyo, Japan 221Filed: Nov. 3, 1971 21 Appl.No.: 195,180

[30] Foreign Application Priority Date Nov. 6, 1970 Japan 45/97118 [52][1.8. CI. 180/33 B, 180/72 [51] Int. Cl 362m 17/00 [58] Field of Search180/33 A, 33 B, 33 R, 180/32, 64 R, 65 R, 72

[56] v References Cited UNITED STATES PATENTS 5/1961 Gourley 180/33 Aug.28, 1973 Primary Examinerl(enneth 1-1. Betts Attorney-Eric H. Waters eta1.

[ ABSTRACT A motorized two-wheel vehicle has an engine supported fromthe frame via resilient damping members and the vehicle is provided witha power transmission from the engine to a rear wheel driven member suchthat the drive of the rear wheel is substantially unaffected by enginevibration. The power transmission comprises a drive member driven fromthe output shaft of the engine by a universal joint, the drive memberbeing coupled to the driven member by a transmission member such as achain, the driven member being connected at the free end of a forkhaving its other end pivotably connected to the frame.

5 Claims, 3 Drawing Figures r v Patented Aug. 28,1973

INVENTORS W POWER TRANSMISSION APPARATUS IN A MOTORIZED TWO-WHEELVEHICLE BACKGROUND OF THE INVENTION 1. Field of the Invention Theinvention relates to a power transmission apparatus for the rear wheelof a motorized two-wheel vehicle.

2. Description of the Prior Art It is conventional for the internalcombustion engine of a motorized two-wheel vehicle to be attached to thevehicle frame through a resilient member for preventing the vibration ofthe engine from being transmitted to the vehicle frame. However, in thiscase it is common for the driving chain to become loosened by thevibration of the engine.

SUMMARY OF THE INVENTION An object of the invention is to obviate theforegoing deficiency and to provide stability of control andvibration-free connection between the engine and frame.

According to the invention, a driving member such as a driving sprocketis rotatably attached to the vehicle frame and the driving sprocket isconnected through a universal joint to the output shaft of an internalcombustion engine attached to the frame through a resilient member, anda power transmission member such as a driving chain is engaged betweenthe driving member and a rear wheel driven member such as a drivensprocket. The rear wheel driven member is mounted on the free end of arear fork pivotably attached directly to the frame.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation view of amotorized twowheel vehicle with a power transmission apparatus accordingto the invention,

FIG. 2 is an enlarged sectional view of the power transmissionapparatus, and

FIG. 3 is a sectional view taken along the line III-III in FIG. I. I

DETAILED DESCRIPTION Referring to the drawing and particularly to FIG.3, an internal combustion engine 2 is attached to a vehicle frame 1 viaresilient members 3, made of rubber or the like, in order to dampvibration from the engine to the frame. A driving sprocket 5 has anintegral shaft 5 rotatably supported in a bearing 6 secured to theframe 1. Ah output shaft 4 of the engine 1 and the driving sprocket 5are interconnected through a universal joint 7 so that power can betransmitted even when the relative position between the shaft 4 and thesprocket 5 is changed.

The universal joint 7 is illustrated in FIG. 2 and is of type using aflexible member of rubber, metal or the like. Numeral l2 denotes a rearfork, numeral 13 denotes a shaft pivotably attaching the rear fork 12directly to the frame 1 so that the fork 12 is swingable upwards anddownwards. Numeral l4 denotes a rear wheel sprocket and numeral 15denotes a driving chain engaged between the driving sprocket 5 and therear wheel sprocket 14. It will be easily understood that the chaindrive type can be modified to a shaft drive type.

By virtue of the foregoing construction, vibration of the engine 2 isabsorbed by the universal joint 7 and does not affect the driving member5. Accordingly, the relative position between the driving member 5 andthe driven member 14 does not change so that the applied condition ofthe power transmission member 15, i.e., the driving chain, can be alwayskept constant and consequently the power can be transmitted smoothly.Additionally, since the rear fork I2 is pivotally attached directly tothe vehicle frame 1, the rigidity of the pivot portion is not loweredand the control property becomes good and the driving becomes stable.Accordingly, the requirement for the resilient attachment of the engineto minimize vibration transmittance and the requirement for thestability of control are fully met by the construction according to theinvention.

What is claimed is:

1. For a two-wheel vehicle having a vehicle frame, an engine supportedfrom the frame and a rear wheel driven from the engine: a powertransmission between the engine and the rear wheel comprising a drivingmember rotatably supported by the frame, a driven member coupled to therear wheel in driving relation therewith, a power transmission memberconnecting the driving member and the driven member, means supportingthe driven member from the frame for displacement relative thereto,means including a resilient damping member connecting the engine to theframe, said engine having an output shaft, and means comprising auniversal joint drivingly connecting the output shaft of the engine andthe driving member.

2. The combination as claimed in claim 1 wherein the means supportingthe driven member from the frame comprises a fork member having frontand rear ends, means pivotably connecting the front end of the fork tothe frame, and means connecting the driven member to the rear end of thefork.

3. The combination as claimed in claim 2 wherein the driving and drivenmembers are driving and driven sprockets and the power transmissionmember is a driving chairi.

4. The combination as claimed in claim 2 wherein the universal jointcomprises a shaft with integral balls at opposite ends thereof, theoutput shaft of the engine and the driving member being provided withrespective bores, and means connecting the balls in respective bores.

' 5. The combination as claimed in claim 4 wherein the means connectingthe balls in the bores comprises pins in said balls, said pins beingslidably accommodated in respective slits provided in the shafts at saidbores.

1. For a two-wheel vehicle having a vehicle frame, an engine supportedfrom the frame and a rear wheel driven from the engine: a powertransmission between the engine and the rear wheel comprising a drivingmember rotatably supported by the frame, a driven member coupled to therear wheel in driving relation therewith, a power transmission memberconnecting the driving member and the driven member, means supportingthe driven member from the frame for displacement relative thereto,means including a resilient damping member connecting the engine to theframe, said engine having an output shaft, and means comprising auniversal joint drivingly connecting the output shaft of the engine andthe driving member.
 2. The combination as claimed in claim 1 wherein themeans supporting the driven member from the frame comprises a forkmember having front and rear ends, means pivotably connecting the frontend of the fork to the frame, and means connecting the driven member tothe rear end of the fork.
 3. The combination as claimed in claim 2wherein the driving and driven members are driving and driven sprocketsand the power transmission member is a driving chain.
 4. The combinationas claimed in claim 2 wherein the universal joint comprises a shaft withintegral balls at opposite ends thereof, the output shaft of the engineand the driving member being provided with respective bores, and meansconnecting the balls in respective bores.
 5. The combination as claimedin claim 4 wherein the means connecting the balls in the bores comprisespins in said balls, said pins being slidably accommodated in respectiveslits provided in the shafts at said bores.